Electrical signal system for traffic lights



June 30, 1953 A. R. FINN ETAL ELECTRIC SIGNAL SYSTEM FOR TRAFFIC LIGHTS Filed March 4, 1949 2 Sheets-Sheet l Patented June 30, 1953 UNITED STATES PATE T OFFICE ELECTRICAL SIGNAL'SYSTEM FOR I TRAFFIC LIGHTS Alfred R. ,Finn, Leaside, Ontario, and Louis Rostoker, Toronto, Ontario, Canada Application March 4, 1949, Serial No. 79,582

' In Canada June 14, 1948 4 Claims. (Cl. 340-41) after referred to as armature meansfserving as a switching means for electrical relay mechanisms governing the actuation of the trafiic lights at a plurality of street intersections.

A further object of the invention is to provide armature means as before designed to actuate said relays to provide a cycle of operation in the lighting system in an installation at an intersection wherein the armature is divided into switching segments whereby the lights are caused. to be actuated in one color arrangement for part of said cycle and in another color arrangement for the remainder of said cycle.

vide armature means as before wherein the rate of rotation of said armature, that is to say the cyclic period thereof, is adjustable by adjusting the gear device ratio for the same and the time period represented by the switching segments thereof is selectable by the operator whereby various proportions of the complete cyclic time may be chosen to decrease or increase the time period for one color of light for a particular street of a traffic intersection.

A still further object of the invention is to provide switch means in said electrical circuit arrangement whereby the light colors may instantaneously be reversed as between corners and intersections.

A still further object of the invention is to provide a switch control box for traffic signal systems which is controllable by simple positive switch means rather than complicated dial systems and wherein a wiring service by a technician at the installation is eliminated by virtue of a simple contact bar means reversibly connecting the mounting panel for the components comprising the circuit arrangement of the present invention in the control box.

A still further object is to provide a control box as before which may be serviced by removing the control unit embodying the circuit arrangement of the invention and replacing the same within a. few minutes without disturbing the control unit wiring to the lights at the intersection.

A still further object of the invention is-to provide in an electrical circuit arrangement for trafiic signal systems relays governed in operation by rotary armature switching means as before wherein the switching segments of the latter constitute low current time contacts only which arev separate from the main current supply systemlfeeding the traffic light, but only govern the actuation of relay switches for actuating these lights and wherein the said relays are mechani- Cally interlocked so that actuation of the same I is impossible under electrical current failure.

With these and other objects inview, the inventionconcerns the provision of low current armature switching means as described governing actuation of relay mechanisms which in turn govern actuation of traflic signal lights at a'traffic intersection. The armature switching means is in the form' of a radially sweeping switching bar which rotates 360 degrees within a period of time determined by the drive ratio of the particular driving mechanism. Switching segments are concentrically arranged relatively to the mounting .of-the switch bar, the innerring of segments being electrically connected to control the actuation of relays governing green and red lightsat an intersection. Switch means are provided whereby the first interval or portion of the complete cyclic period.- can be chosen for a selectable period of time whereby the lights remain at a'ifixed switching during this period or interval.. The remainder'of the cyclic period is devoted to an opposite lighting arrangement, that is to say green instead of red on opposite Corners north and south by virtue of the electrical connection of the remaining segments to a relaying controlling this opposite operation.

The invention alsonconcerns the provision of a reversing switch mechanism interposed between the relays and the armature means Whereby the switching control affected by the armature means is switched over' on to opposite relays to cause a direct reversal or change to opposite Figure 1 is an illustrative schematic of the Figure 4 is a front elevation of a complete control unit for a traffic signal system at an intersection illustrating the novel assembly of the components.

Figure 5 is a side elevation of the unit of Figure 4 with the side casing removed.

Figure 6 is a partial View showing the drive motor for the armature Of Figure and the gear mechanism therefor.

Figure '7 is a partial view of the components provided for building up any switching segments by interconnecting the contact buttons shown in the preferred form of the armature switching means in Figure 4.

Figure 8 is a schematic view of a manual switching arrangement by which the operator may cause manual actuation of the traffic signal lights in the event of failure of the automatic system embodying the armature switching means of the invention.

Referring to the drawings, and particularly to Figure 1, the relay coils III, II, I2 and I3 are connected at one end thereof to the line I4 of a conventional electrical current supply. The relay coil I governs actuation of the contacts I5 and I 6. The contacts I5 governing actuation by conventional electrical circuit arrangement of the green lights at say north and south of an intersection. The contacts I6 govern actuation of the red lights as the east and west light installation when the coil Ill is energized. Coil II actuates contacts I! and IS, the contact II providing actuation of the green lights at the east and west, the contact I8 actuating the red lighs at norh and south.

The yellow or orange lights areactuated by the coils I2 and I3 governing the contacts I9, 20, 2| and 22 corresponding respectively to north. south, east and west lights.

In the description which follows, for simplification the actuation of contacts I5 and I! for effecting operation of the green lights will only be discussed since it will be obvious that if the contact I5 is closed actuating the green lights at north and south then the red lights at east and west will be actuated by virtue of closure of contact l6.

Instantaneous reversal switching means are included which comprise, in the simple illustration shown, the switch arms 23 and 24 engaging the switch contacts 25 and 26. The coil I0 is connected to contact 25 and the coil I I to contact 26. The coil It also being connected to contact 21 by line 28 so that the switch arms 23 and 24 may engage contacts 26 and 21 in the alternate position. Obviously, therefore, if the green lights were east and west as governed by coil II in the disposition of the switch arms 23 and 24 as shown and assuming that current was being supplied only through the switch arms 24 to energize the coil I I but not through the switch arm 23 so that the coil ID will not be energized, then. if the switch 4 arms are moved to position engaging contacts 26 and 21 respectively the green light will be switched to north and south instantaneously.

Instantaneously reversing switching means are also provided governing the yellow or orange lights, that is to say, the coil I2 and I3, thus the switch arms 29 and 30 are. shown engaging the contacts 3| and 32 connetced to the coils I2 and I3 respectively. The coil I2, however, also connects by the line 33 to the contact 34 so that in a reversing switching position the switch arms 29 and 30 may engage the contacts 32 and 34 respectively. 'In the arrangement shown, if it is assumed that only the switch arm 30 is carrying electrical current but that the switch arm 29 is not, then the east and west yellow lights may be actuated at the appropriate time after the green lights at east and west have been showing for a predetermined period. Obviously in such instance, therefore, if the switch arms 29 and 30 reversed to engage the contacts 32 and 34 the yellow lights will show at north and south. In order to provide a common function the switch arms 23, 24, 29 and 30 are operatively ganged together as indicated by the chain lines and numeral 35. Therefore, the operator may instantaneously cause a change in the lighting by merely actuating a gang switching mechanism. For the switching mechanism in practical form, I prefer to use double pole double throw toggle switches, but obviouslyany other suitable switching arrangement which will carry out the necessary functions above outlined will serve.

According to the invention, rotary armature switching mechanism 36 is provided which is illustrated in diagrammatic form only in Figure 1 in the form shown. The contact bar 3 extends from electrical connection to the ring 38 which is in turn connected by the line 33 to the other line 40 of the current supply source, to contact the concentric switching rings 4| and 42 which are in the form of a plurality ofsegments. The contact bar 31 is caused to rotate in this illustration in a counter-clockwise manner at a predetermined cyclic rate, hereinafter referred toas a cyclic period. According to the invention a portion of this cyclic period is used to actuate say the coil II, causing the east and west green lights to be actuated.- The remainder of the cyclic period is apportioned to the relay coil I0 so that the north and south green lights will be actuated for the remainder of the period.

The above function is accomplished by providing switching segments in the inner and outer rings 4| and 42. The inner ring II ,is designed to govern the actuation of green and red lights only, whereas the outer ring is designed to govern actuation of the yellow or orange light only, that is to say the caution light.

As shown, the arrangement in Figure 1 illustrates the actuation of the green light by the coil II at east and west for one-half the cyclic period of the contact bar 31. Thus the switching segment 43 extends about degrees in an arcuate manner as illustrated and is connected at some point to the line 44 which extends for connection to the switch bar or arm 24 as illustrated. Thus, when the contact bar 31 is passing around this portion of its cyclic period the coil II will be energized causing the green light to show at east and West and the red lights to show at north and south. After a certain period of time the yellow or caution light must be actuated at east and west for the remainder of the greenlight period at these stations. There-.

fore, the switching segment 45 is positioned at the end of the electrical connecting period of the segment 43 and connects by line 46 through contact 4? switch arm 48 and common line 49 to the switch arm 30 for energization of the coil 3 and actuation of the caution lights at east and West.

After the contact bar 31 passes the ends of the switching segments 43 and 45 it will engage the inner ring switching segments 50, 5| and 52 in turn feeding current to the same. It will also engage the outer ring switching segments 53, 54 and 55 in turn. The segment 50 is connected by line 56 through contact 51 and switch arm 58 (as shown) to contact 59 and the line 69 connects to the arm 23. The segment 5| is connected by the line 6| to the switch arm 62 and through contact 63 (as shown) to the line 66. The last switching segment 52 is connected by the line 64 to the line 60 as illustrated.

It will be aparent, therefore, that as the contact bar passes the end of the inner ring switching segment 43 it will feed current by way of segments 56, 5| and 52 through lines 56, BI and. B4 consecutively to the line (it and switch arm 23 to energize the coil It and cause the lights to show green at north and south during this second half cyclic period.

If, however, it is desired that the period of the switching segment 43 be prolonged, then the switch arm 58 may be caused to move to a position engaging the contact 65 which in connection by line 66 to line 44 and switch arm 24. Obviously, therefore, in such instance the green light would be continued in its actuation by the coil H until the contact bar 31 has passed the end of the segment 50 and then the remainder of the cycle would be apportioned to contacting the segments 5! and 52 actuating the green light at the north and south.

Further, the switch arm 62 may be moved to engage the contact 51 as well as arm 58 engaging the contact 65 in which case the period of actuation of the coil It would correspond only to the arcuate length of the switching segment 52 and the time period of the actuation of green lights at east and west would be a further segment unit longer.

The arrangement of the concentric switching rings for the operation discussed with regard to switch arm 58 engaging contact 65 is illustrated in Figure 2 wherein a continuous segment 43a is illustrated corresponding to the segment 50 added to the segment 43. The segment 5la illustrates the tying together of the segments 51 and 52 illustrating the apportionment of the time periods within a cyclic period to actuation of the green lights at east and west and at north and south respectively.

Figure3 illustrates the switching segments 43b of extended length corresponding to engagement of the arm 58 with contact 65 and the arm 62 with contact 51. Segment 52a is illustrative of the remaining period provided for the green lights at north and south.

The outer switching ring 42 is provided for actuating the caution lights and is divided into similar segments to correspond with the time period functions in the inner ring. Thus the segment 53 is connected by the line 51 to contact 68 which is designed to be engaged by the switch arm 59 connected to line 49. The segment 54 is connected by line to contact H designed to be engaged by switch arm 12 connected to the line 49 as shown. Thus for the 6. operation illustrated in Figure 2 and previously described with regard t9 the green lights only, it is desired that the segment 53 be utilized only for the caution light for the period correspond-i ing to the continuous segment 43a. In this connection, therefore, the switch arm 48 must be moved out of engagement with contact 41 toprovide an open circuit therefor. Thus the contact bar will not cause actuation of the yellow light at east and west when passing over the segment 45 but will only do so when it engagesthesegment 53 which must in this instance have its contact 68 engaged by switch arm 69. After the contact bar passes the segments 53 and 5B the green light will be actuated at north and south and at the end of the cyclic period the segment 55 will be engaged, the latterbeing directly connected by the line 13 to the switch arm 29 as illustrated. Thus, at this point the coil l2 will be energized causing the caution light to show at north and south. I

Referring to Figure 3 the operation is substantially similar to that previously discussed except that the initial period for the coil II is longer, as illustrated by the segment 43b. In this case, therefore, both the switch arms 43 and the switch arms 69 must be away from and in open circuit relation to the contacts 41 and 68, but the switch arm 12 is in engagement with the contact H, thus the caution light will show toward the end of the period of the segment 43 at east and. west and will show apparently for the full period of the segment 52a to give a caution light at north and south. This last illustration is not really practical but, nevertheless, illustrates the limits of the principle involved.

In conventional trafiic signal systems if a breakdown in a part of the mechanism occurs it is necessary for a traflic director to enter into'the intersection and direct the traffic by hand signal. At a congested intersection this. is dangerous to the traffic director as well as involving all the other disadvantages of handling traffic in this manner as compared with an automatic system, thus according to the invention manual actuating means are provided whereby upon failure of the armature means described, should this unlikely event occur, the traffic director need merely actuate simple manual switching means while adjacent to the control box; In this connection the trafiic director or operator may-allow any period of time he desires for a particular signal on one street. Thus it may be desirable at times for the operator in any case to switch to manual operation to take care of particular conditions arising in the congestion of traflic at an intersection.

The manual switching means which are .provided are illustrated in Figure 8 in diagrammatic form. Reference is also made to Figural wherein a control switch means 74 are comprised of the switch arm 15 connecting to the line 4!) and normally engaging the contact 16 of the line 39 for automatic operation with the armature mechae nism previously described. In the manual position the arm 15 engages the contact ll which connects by the line 18 to the rotary switch arm 19 of the rotary manual switch means 89.

The switch arm 9 is shown in the normal off position or intermediate position and engaging the contacts 8i and 82 which: are not connected to any certain components. The contacts 83 and 84 are tied together as indicated by the line 85 and are connected by line 86 to the coil H as indicated thereby governing the green lights at east and west. The position of the switch arm 19 at the contact 83 corresponds to the green lights alone at east and west, whereas the position of this arm engaging contacts 84 and 81 corresponds to the green light together with the caution light at east and west since it will be noted that the contact 81 connects to the line 88 to the relay coil I3.

' A similar arrangement is provided in the opposed portion of the switch wherein the contacts 89 and 90 are interconnected by the line 9 I. The contact 90 connects by the line 92 to the coil I0. The contact 93 governing the caution light connects by the line 94 to the coil I2. It will be apparent therefore that the operator after insuring that the manual switch means are closed need merely rotate the rotary switch manually to the four positions illustrated to cause the desired operations in the control of traffic. The switch arm 19 may be moved first to the right to cause the green light to show at east and west and then after a suitable length of time switch to engage the contacts 84 and 81 to give a caution signal at the east and west lighting groups. After sufficient caution signal has been given the operator moves the switch arm in the counter-clockwise direction until it engages the contact 89 causing the green light to show at north and south and after a sufficient period of time moves the arm 19 further to engage the contacts 90 and 93 to ive a caution signal. Operation continues thereafter in the same manner until manual operation is no longer desired at which time the operator may switch the arm 19 to the mutual off position illustrated. Certain features attend the mounting of the component parts found in the circuit arrangement above described. All of the components are of conventional and well known construction but the novel arrangement which I have devised leads to many advantages in maintenance of a traflic signal control box unit.

Thus, in Figures 4 to '7 the housing 95 has the bracket means 96 and 91 extending inwardly thereof. The upper brackets 96 mount the connecting panel 98 which carries the main control knife switch means 99 governing the operation of the complete unit. A pilot light I is preferably included to indicate when the unit is switched on. The connecting panel 98 carries a plurality of bracket means IOI similar to conventional fuse clips and near to the edge thereof in spaced apart relation to receive the contact bar means or lugs I02 which if desired may be fuses. The bracket means IOI are connected to wires which are bound within the cable I03 as illustrated in Figure which extends down to present all of the leads to separate contacts I04 on the terminal mounting block I05 from which connection is made to the traffic lights at an intersection. The portion of the unit so far described is designed to be permanently installed.

A removable panel I06 is provided which is fastened to the brackets 96 and 91 by suitable screws or other fastenin means I01 and I08. The plurality of contact bar sockets I09 are arranged along the upper edge of the panel I06 to receive the other ends of the contact bars I02 which are easily removable therefrom, the brackets I09 of the electric leads extending therefrom which are bound into the cable H0 and where these leads are required for the components of the electrical circuit arrangement they are led out as indicated in Figure 5 for connection at the back of the panel I06. Electrical relays I0a, Ila, I21; and Ho are mounted on the front face of the panel as shown. These relays may be of any suitable form but according to the invention should call for very low current drain, but the contacts thereof should be of sturdy construction. The form shown is a commercial form in which the coil III is connected by leads H2 and H3 to one side of the main current supply line and to the reversing switch means I I4 according to the circuit arrangement shown in Figure 1. The contact arms I I5 and I I6 are connected by leads H1 and H8 to the caution lights at south and north respectively as illustrated with continuity with regard to the arrangement of Figure 1. It will be noted that the contact arms are of the pivotally mounted type pivoted substantially intermediate of the ends. I provide interlocking means II9 to ensure positive operation and security against faulty operation of relays so that for instance a red signal will not show simultaneously at both east and west and north and south. The interlocking means comprising the rocker arm I20 pivotally mounted on the bracket I2I the ends of which are extended to be engaged by the contact arms of the relays I2a and I301. and a similar arrangement is provided for the relays I01: and II a. The contact arms H5 and H6 are rigidly connected at one end by the common bar I22 extending there between and a similar structure is in evidence in the other relays. The rocker arm is sopositioned relative to the contact bars I23 that only one relay of each interlocked pair can be actuated at any one time. Thus, in Figure 5 either of the relays I3a or I2d may be actuated. Obviously if the contact arms of the relay I 20. wererotated clockwise to the closed position the rocker arm would prevent the actuation of the other relay I3a by engagement with the contact bar I23a thereof thus preventing closing of the contacts of this relay.

The armature device 36 in this instance is comprised of the inner ring of contact buttons I 24 which are designed to be engaged by a simple stud or brush I25 extending from the contact bar I26, this arm being mounted on the shaft I21 which causes rotation of the same in a counterclockwise direction in the illustration shown. The bar I26 is preferably a solid bar of metal which is electrically insulated from the shaft I21 therefor providing electrical connection between the brushes I28 and I 29 as well as. the brush I25, brush I 28 at all times engaging the surface of the contact ring I290. which corresponds to the contact ring 38 in Figure 1 and electrically connected in the manner illustrated there. The outer ring is comprised of a plurality of contact buttons I30 and has a portion thereof made up of the continuous segment I3l which is not connected electrically to any of the components in the circuit arrangement involved.

Referring to Figure 6, the contact bar I26 is driven preferably by a synchronous motor I32 mounted on a bracket I33 which extends from connection to the panel I06 and presents a rotating shaft I34 carrying the pinion I35 which drives the gear wheel I36 causing rotation of shaft I21. In order to provide for a difierent cyclic period of rotation of the bar I26 the gear I31 may be caused to be engaged by the pinion I35 instead of the gear I36 by moving the pinion I35 along shaft I34 and again fastening it with its screw I38 and moving the motor I32 transversely by first loosening the mounting bolts I39 until the pinion I35 is in engagement with the gear I31. By this simple arrangement therefore means are provided for changing the cyclic period of the arm 126, that is to say the armature means.

Interconnected toggle switches I40, MI, and M2 are arranged for changing the portion of the cyclic period allotted to either east and west lights or north and south lights. It will be realized that the switches I42 say correspond to the switch arms 69 and 58 of the circuit diagram of Figure 1. Obviously the function to be accomplished by this combination could be provided in a double pole double throw switch mechanism if desired. The single switch means M3 correspond to the single switch arm '38 governing the actuation of the first caution light segment 45, see Figure l. The switch means 145 correspond to the automatic and manual switch illustrated in Figure l and designated by numeral it. The manual switching arrangement indicated by numeral 145 is arranged conveniently on the panel and is preferably comprised of a two gang rotary switch arrangement satisfying the functional requirements discussed with reference to Figure 8 previously. Appropriate legend its are placed on the dial plate Ml in conjunction with the indicating knob M8 so that the operator can see. clearly what operation is expected from each position of the switch knob.

In the previous discussion concerning Figure 1 the apportionment of parts of the cyclic period the armature means was discussed with reference to the provision of segments in the form of parts of concentric rings. The buttons I24 and Kit are an equivalent of this simplified arrangement since as desired the buttons may be interconnected. This is provided by the simple means illustrated in Figure 7 where as an example a series of the buttons 12 are shown mounted in the panel Hit the heads I49 and H50 of the studs i! and IE2 being of sufficient diameter that the brush i25 smoothly engages the next before it leaves the last in its path of movement thereover. Each buttonhead I24 is made similar to the studs ibi \vhich has a shaft I53 which is passed through a hole in the panel Hit and is fastened to the latter by means of the washer I54 and nut i575 on the threaded shank portion iEB thereof. Connecting links l5l are placed overthe shafts of adjacent buttons to be connected together and supported by suitable nuts I58 and fastened thereto by the overlying nuts H59. If it is desired to separate adjacent contacts electrically a connecting link may be removed from between the same thus it is possible by simply removing the panel to adjust the lengths of the segments desired in the inner and outer rings so that the initial period may be one minute for the green light at east and west when the contact bar 525 is traveling up the right-hand side of the armature arrangement as illustrated, this adjustment being made on the contact buttons 624. After this adjustment the other adjustments may be made in a similar manner so that the switch means I49, i4! and :s2 will give the added por tion of the time of the green light east and west for the arrangement shown. In this illustration it'will be obvious that the cyclic period of the armature means is two minutes, with segments being formed in the inner and outer rings by appriopriate arrangement of the connecting links I51 to give additional five second intervals which.

may be selected by the operator.

It will be apparent that if for any reason the device described fails to operate satisfactorily then a service man may be called who may bring a substitute panel and install the same without materially interfering with the operation 01 traf- 10 fic even at a busy intersection. The service man is merely required to remove the contact bar members I02 after opening the switch 99 and then loosening the bolts I01 and its to remove the complete panel from the housing. The substituted panel may be immediately placed in, bolted down and the contact bars inserted. During the short interval of time required for this operation the traiiic director may enter into the intersection to direct the traflic by hand signals.

The provision of a low current control system consisting of the armature mechanisms described to govern the relays actuating the lights avoids the serious disadvantages of having a plurality of switching contacts burn out due to arcing. and pitting. By virtue of the low current drain required by the coils of the relays no arcing is experienced in thepassing of the contact brushes 0f the arm I25 over the contact buttons. vThe life of this mechanism is therefore substantially, only limited by the life of the drive motor or the mechanical mechanism driving the same.

It will be apparent that I have provided a particularly simple and effective electrical circuit arrangement and control unit for traffic light signal systems which attains the objects outlined and which includes the most advantageousfeatures of an instantaneous reversing switch. The operation of the device requires a minimum of supervision by the operator in the event that the traffic times need to be changed which is a distinct advantage where crowded trafic conditions require the supervision of the traffic director without requiring his attention to the signal light system except for brief moments for slight adjustments in time periods. The manual switch means provided is a'distinct improvement which allows the trafiic director to carry on in the unlikely event that the relays or the armature mechanism breaks down.

The circuit diagrams illustrated herein are particularly simplified as compared to conventional circuit diagrams of traffic signal systems. It will 0 be appreciated, however, that many modifications will be apparent to skilled persons not only in the circuit arrangements embodying the principal set-up, but also in the particular components chosen for carrying out the functions desired. It is not intended therefore that the i1- lustrations herein should be interpreted in any sense which would limit the use of various types of switching mechanisms and relays or the specific structure of the armature arrangement. It is intended therefore that the present disclosure should not be construed in any limiting sense other than that indicated by the scope of the following claims.

What we claim as our invention is:

' L In an electrical signal system for traffic lights including aplurality of relays governing the actuation of said lights and electrically arranged so that one relay is designed to actuate the green lights at east and west and the red lights at north and south, a second relay is designed to actuate green lights at north and south andred lights at east and west, 2. third relay.

is designed toactuate caution lights at north and south, and a fourth relay is designed to actu-.

portioning part of said cyclic period by electrical connection to said second relay, means for apportioning the remainder of said cyclic period by electrical connection to said first relay, said armature means being connected to one side of a current. supply line and distributing current therefrom according to said apportionment, said relays being commonly connected to the other side of said current supply line, and means feed-.

ing electrical current to said third relay during the last portion of the portion of the cyclic period apportioned to said second relay and means feeding electrical current to said fourth relay at the end portion of said cyclic period.

2. In an electrical signal system for trafiic lights including a plurality of relays governing the actuation of said lights and electrically arranged so that one relay is designed to actuate the green lights at east and west and the red lights at north and south, a second relay is designed to actuate green lights at north and south and red lights at east and west, a third relay is designed to actuate caution lights at north and south, and a fourth relay is designed to actuate caution lights at east and west; a control electrical circuit arrangement for actuatingthe relays comprising; a contact bar, means for sweeping said contact bar radially'in one direction only to provide a predetermined fixed cyclic period therefor, said contact bar being electrically connected to one side of a current supply line, said relays being connected to the other. side of said current supply line, a switch segment engageable by said contact bar and electrically connected to said first relay to complete the electrical circuit thereof, another switching segment designed to be engaged by said contact bar after engagement of the first switching segment thereby and normally electrically connected to said second relay for completion of the electrical circuit thereof when engaged by said contact bar, and time period switch means interposed between said other switching segment and said first relay whereby the circuit to said relay may be opened and said first switching segment placed in closed circuit relation with said other switching segment.

3. In an electrical signal system for traffic lights including a plurality of relays governing the actuation of said lights and electrically arranged so that one relay is designed to actuate the green lights at east and west and the red lights at north and south, a second relay is designed to actuate green lights at north and south and red lights at east and West, a third relay is designed to actuate caution lights at north and south, and a fourth relay is designed to actuate caution lights at east and west; a control electrical circuit arrangement for actuating the relays comprising; a contact bar, means for sweeping said contact bar radially to provide a predetermined cyclic period therefor, said contact bar being electrically connected to one side of a current supply line, said relays being connected to the other side of said current supply line, a switch segment engageable by said contact bar and electrically connected to said first relay to complete the electrical circuit thereof, a second switching segment spaced from said first switching segment and designed to be engaged by said contact bar during a portion of the period of its travel over said first switching segment, a third switching segment designed to be engaged by said contact bar after engagement of the first switching segment thereby and normally electrically connected to said second relay'for completion of the electrical circuit thereof when engaged by said contact bar, and reversing switch means interposed between said relays and the electrical connections to said third switching segment, said first switching segment and said second switching segment whereby said first segment may be connected to said second relay, said second segment may be connected to said third relay and said third segment may be connected to said first relay.

4. In an electrical signal system for traffic lights including a plurality of relays governing the actuation of said lights and electrically arrange so that one relay is designed to actuate the green lights at east and west and the red lights at north and south, a second relay is designed to actuate green lights at north and south and red lights at east and West, a third relay is designed to actuate caution lights at north and south, and a fourth relay is designed to actuate caution lights at east and west; a control electrical circuit arrangement for actuating the relays comprising; electrical control armature means having a cyclic period, means apportioning part of said cyclic period by electrical connection to said second relay, means for apportioning the remainder of said cyclic period by electrical connection to said first relay, said armature means being connected to one side of a current supply line and distributing current therefrom according to said apportionment, said relays being commonly connected to the other side of said current supply line, and means'feeding electrical current to said third relay during the last portion of the portion of the cyclic period apportioned to said second relay, means feeding electrical current to said fourth relay at the end portion of said cyclic period, and reversing switch means interposed electrically between said relays and said control circuit arrangement whereby the control initiated by said armature control means may be oppositely directed electrically to switch the electrical c1rcuit arrangement of the control armature to serve initially the first and third relays and latterly the second and fourth relays within the cyclic period of said control armature.

ALFRED R. FINN. LOUIS ROSTOKER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,532,452 Spaller Apr. 7, 1925 1,821,000 Bissell Sept. 1, 1931 1,923,893 Smith Aug. 22, 1933 2,053,110 Regan Sept. 1, 1936 2,227,993 Anderson Jan. 7, 1941 2,461,236 Rostoker Feb. 8, 1949 FOREIGN PATENTS Number Country Date 334,928 Great Britain Sept. 15, 1930 354,409 Great Britain Aug. 13, 1931 

